I. Field
The following description relates generally to wireless communications, and more particularly to schemes for fast access of resources.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Wireless communication systems have become a prevalent means by which majority of people worldwide have come to communicate. Wireless communication devices have become smaller and more powerful in order to meet consumer needs, improve portability and convenience. The increase in processing power in mobile devices such as cellular telephones has lead to an increase in demands on wireless network transmission systems.
A typical wireless communication network (e.g., employing frequency, time, and code division techniques) includes one or more base stations that provide a coverage area and one or more mobile (e.g., wireless) terminals that can transmit and receive data within the coverage area. A typical base station can concurrently transmit multiple data streams for broadcast, multicast, and/or unicast services, wherein a data stream is a stream of data that can be of independent reception interest to a mobile terminal. A mobile terminal within the coverage area of that base station can be interested in receiving one, more than one or all the data streams carried by the composite stream. Likewise, a mobile terminal can transmit data to the base station or another mobile terminal.
In a Long Term Evolution (LTE) systems, a random access channel (RACH) may be used when a terminal or user equipment (UE) requires resources for establishing a connection with base station (for example Node B or access network). The random access channel parameters are periodically broadcasted by Node B on the downlink common control channel (CCCH) or one of the broadcast channels (BCH). UE may transmit over RACH only after it achieves downlink synchronization and obtains the most current RACH parameters. The RACH is also used for Uplink layer 1 synchronization and requesting uplink air link resource assignment. In the orthogonal nature of the uplink air interface (for example OFDM or OFDMA systems), it may be necessary that RACH resources be reserved and used only for access. Utilization of RACH is bursty and may be much lower than the utilization of the scheduled traffic data channel. Therefore, a need exists that minimum time/frequency resources be assigned to RACH while ensuring short access delays.